Hello,
Any news on this?
Samuel
Samuel Thibault, le ven. 29 mai 2020 13:46:50 +0200, a ecrit:
> Hello,
>
> libgcc is currently missing the support for unwinding over signal
> trampolines on GNU/Hurd. The attached patch implements it.
>
> Samuel
> hurd: libgcc unwinding support over signal trampolines
>
> * libgcc/config.host (md_unwind_header): Set to i386/gnu-unwind.h on
> i[34567]86-*-gnu*.
> * src/libgcc/config/i386/gnu-unwind.h: New file.
>
> diff --git a/libgcc/config.host b/libgcc/config.host
> index 2cd42097167..044b34d53cc 100644
> --- a/libgcc/config.host
> +++ b/libgcc/config.host
> @@ -734,11 +734,17 @@ i[34567]86-*-linux*)
> tm_file="${tm_file} i386/elf-lib.h"
> md_unwind_header=i386/linux-unwind.h
> ;;
> -i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-gnu* |
> i[34567]86-*-kopensolaris*-gnu)
> +i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-kopensolaris*-gnu)
> extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
> crtfastmath.o"
> tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
> t-dfprules"
> tm_file="${tm_file} i386/elf-lib.h"
> ;;
> +i[34567]86-*-gnu*)
> + extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
> crtfastmath.o"
> + tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
> t-dfprules"
> + tm_file="${tm_file} i386/elf-lib.h"
> + md_unwind_header=i386/gnu-unwind.h
> + ;;
> x86_64-*-linux*)
> extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
> crtfastmath.o"
> tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
> t-dfprules"
> diff --git a/src/libgcc/config/i386/gnu-unwind.h
> b/src/libgcc/config/i386/gnu-unwind.h
> new file mode 100644
> index 00000000000..db47f0ac1d4
> --- /dev/null
> +++ b/src/libgcc/config/i386/gnu-unwind.h
> @@ -0,0 +1,107 @@
> +/* DWARF2 EH unwinding support for GNU Hurd: x86.
> + Copyright (C) 2020 Free Software Foundation, Inc.
> + Contributed by Samuel Thibault <samuel.thiba...@gnu.org>
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify
> +it under the terms of the GNU General Public License as published by
> +the Free Software Foundation; either version 3, or (at your option)
> +any later version.
> +
> +GCC is distributed in the hope that it will be useful,
> +but WITHOUT ANY WARRANTY; without even the implied warranty of
> +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +GNU General Public License for more details.
> +
> +Under Section 7 of GPL version 3, you are granted additional
> +permissions described in the GCC Runtime Library Exception, version
> +3.1, as published by the Free Software Foundation.
> +
> +You should have received a copy of the GNU General Public License and
> +a copy of the GCC Runtime Library Exception along with this program;
> +see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
> +<http://www.gnu.org/licenses/>. */
> +
> +/* Do code reading to identify a signal frame, and set the frame
> + state data appropriately. See unwind-dw2.c for the structs. */
> +
> +#ifndef inhibit_libc
> +
> +#include <signal.h>
> +
> +#define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state
> +
> +static _Unwind_Reason_Code
> +x86_gnu_fallback_frame_state
> +(struct _Unwind_Context *context, _Unwind_FrameState *fs)
> +{
> + struct handler_args {
> + int signo;
> + int sigcode;
> + struct sigcontext *scp;
> + } *handler_args;
> + struct sigcontext *scp;
> + unsigned long usp;
> +
> +/*
> + * i386 sigtramp frame we are looking for follows.
> + * (see glibc/sysdeps/mach/hurd/i386/trampoline.c assembly)
> + *
> + * rpc_wait_trampoline:
> + * 0: b8 e7 ff ff ff mov $-25,%eax mach_msg_trap
> + * 5: 9a 00 00 00 00 07 00 lcall $7,$0
> + * 12: 89 01 movl %eax, (%ecx)
> + * 14: 89 dc movl %ebx, %esp switch to signal
> stack
> + *
> + * trampoline:
> + * 16: ff d2 call *%edx call the handler
> function
> + * RA HERE
> + * 18: 83 c4 0c addl $12, %esp pop its args
> + * 21: c3 ret return to
> sigreturn
> + *
> + * firewall:
> + * 22: f4 hlt
> + */
> +
> + if (!( *(unsigned int *)(context->ra ) == 0xc30cc483
> + && *(unsigned char *)(context->ra + 4) == 0xf4
> +
> + && *(unsigned int *)(context->ra - 4) == 0xd2ffdc89
> + && *(unsigned int *)(context->ra - 8) == 0x01890007
> + && *(unsigned int *)(context->ra - 12) == 0x00000000
> + && *(unsigned int *)(context->ra - 16) == 0x9affffff
> + && *(unsigned short *)(context->ra - 18) == 0xe7b8))
> + return _URC_END_OF_STACK;
> +
> + handler_args = context->cfa;
> + scp = handler_args->scp;
> + usp = scp->sc_uesp;
> +
> + fs->regs.cfa_how = CFA_REG_OFFSET;
> + fs->regs.cfa_reg = 4;
> + fs->regs.cfa_offset = usp - (unsigned long) context->cfa;
> +
> + fs->regs.reg[0].how = REG_SAVED_OFFSET;
> + fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp;
> + fs->regs.reg[1].how = REG_SAVED_OFFSET;
> + fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp;
> + fs->regs.reg[2].how = REG_SAVED_OFFSET;
> + fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp;
> + fs->regs.reg[3].how = REG_SAVED_OFFSET;
> + fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp;
> + fs->regs.reg[5].how = REG_SAVED_OFFSET;
> + fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp;
> + fs->regs.reg[6].how = REG_SAVED_OFFSET;
> + fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp;
> + fs->regs.reg[7].how = REG_SAVED_OFFSET;
> + fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp;
> + fs->regs.reg[8].how = REG_SAVED_OFFSET;
> + fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp;
> + fs->retaddr_column = 8;
> + fs->signal_frame = 1;
> +
> + return _URC_NO_REASON;
> +}
> +
> +#endif /* ifndef inhibit_libc */
--
Samuel
<c> xlnt comme sujet de stage je peux essayer de donner une description
formelle de automake
-+- #ens-mim -+-
